Yarn tensioning device



OGL 11, 1955 W. s. BROWN YARN TENSIONING DEVICE Filed Sept. l5 1'953FIG. l. 3l

VV. S. BROWN ll/vavrof( MMM ATTONE YS United States Patent O YARNTENSIONING DEVICE William Saville Brown, Spondon, near Derby, England,

assignor to British Celanese Limited, a British com- Daily ApplicationSeptember 15, 1953, Serial No. 380,299

Claims priority, application Great Britain September 30, 1952 Thisinvention relates to yarn tensioning devices, and particularly todevices of the kind in which tension is developed in a yarn by theengagement of the yarn with frictional surfaces in contact with whichthe yarn runs.

According to the present invention a yarn tensioning device comprises apair of friction elements disposed faceto-face, one provided with aprojecting ridge and the other with a groove matching and registeringwith said ridge, said elements being pressed together (preferably by theweight of one of them) upon a yarn extending between them and beingadapted to nip said yarn when the tension therein is low and to be movedapart by said tension when it increases. Most conveniently the twoelements are of circular form and are mounted for rotation about acentral axis so that one or both can be rotated slowly by the passage ofthe yarn as is usual in the conventional type of disc tension device.The projecting ridge and the matching groove will then be circular, andconcentric with the axis of rotation of the friction elements, and willbe engaged twice by the yarn as it passes into and out of engagementwith the friction elements. Two or more ridges, and correspondingmatching grooves may be employed if desired.

The tension device of the present invention is particularly useful as acreel tension device in warping opera tions, or in other situations inwhich it is desirable that tension should be maintained on the outputside of the device even after the running of the yarn through the devicehas been stopped. During the running of the yarn the yarn is not nippedbetween the friction elements, the pressure of the yarn against thefriction elements being derived wholly from the tension in the yarn.When the yarn is stopped, however, so that the tension on the outputside of the device may fall away to zero, the friction elements arepressed together so as to nip the yarn and to maintain a pressurethereon independent of the tension in the yarn, whereby tension canstill be maintained on the output side ofthe device. This isparticularly useful in warping operations. The tension device, however,`is not limited to such operations but may be employed generally insituations in which tension devices of the disc type can beused.

In the operation of the device, the separation of the friction elementsby the tension in the yarn reduces the factor by which the tension inthe yarn is multiplied in passing through the device, by reducing theangle of contact made by the yarn with the friction elements.Accordingto a further feature of the invention, however, provision maybe made to reduce the tension ratio still further, independently of theaction of the yarn tension in separating `the friction elements. Wherethefriction elements are circular, and are arranged to rotate, thisrotation (which takes place only while the yarn is inmotion) may beemployed directly or indirectly to increase separation of the elements.Thus, between a fixed central spindle and the upper friction elementthere may be interposed a sleeve, freely mounted on the spindle, and

2,720,366 Patented 0ct. 11, 1955 lCe provided with a helical grooveengaged by a pin or other inward projection from the upper frictionelement. The sleeve can then be provided with a pulley adapted to beengaged by the yarn as it passes between the friction elements, and toimpart to the sleeve a tendency to rotate faster than the upper frictionelement, whereby the helical groove formed in the sleeve and engaged bythe upper friction element tends to lift the upper friction element fromthe lower. Alternatively, the sleeve may be frictionally retarded (e. g.by its engagement with the central spindle) so that the upper frictionelement is lifted by its tendency to rotate faster than the sleeve, thehelical groove being formed, in this case, in the opposite direction tothat used when the sleeve is yarn-driven.

By way of example, two forms of tension device in accordance with thepresent invention will now be described in greater detail with referenceto the accompanying drawing in which,

Figure 1 is an elevation, partly in section on the lines 1-1 of Figure2,` of one form of tension device,

Figure 2 is a plan of the same tension device,

`Figures 3 and 4 are similar views of a second form of tension device,and

Figure 5 is a fragmentary sectional view showing a variation in detailof the tension devices of Figures l-4.

Referring to Figures l and 2, the tension device shown therein comprisesa sheet metal base plate 6 having an up-turned stiening ange 7 and twoobliquely descending flanges 8, 9, folded upon themselves. The plate 6is slotted at 10 for the attachment of a fixed spindle 11 which isadjustably secured by means of a nut 12 beneath the plate 6. Surroundingthe spindle 11 is a sleeve 13 of wear-resisting ceramic material, roundwhich are fitted two friction elements 14, 15. The lower frictionelement 14 is an inverted cup-shaped member, the skirt of which rests onthe base plate 6, while the upper friction element 15 is in the form ofa disc of the same diameter as the lower friction element 14, on whichit rests. Both friction elements are centred by their engagement withthe sleeve 13 which passes through a central hole in each of theelements.

Surrounding and concentric with the central hole in the upper surface ofthe lower friction element 14 is a groove 16 of approximatelysemi-circular section with rounded edges. The upper friction element 15is formed on its under surface with a circular ridge 17 of semi-circularcross-section which tits into the groove 16. The ridge 17 is somewhatdeeper than the groove 16 so that the remaining parts of the faces ofthe two elements`14, 15 are always spaced apart. The elements 14, 15 aremoulded to the required shapes and are made of a hard ceramic materialor other suitable friction material capable about the level of the uppersurface of the lower friction element 14 and mounted in the middle of acircular balloon plate 20 of about 11/2 in diameter. The balloon plate20 has a lug or extension 21, vertically slotted at 22 and adjustablysecured to the flange 8 by means of a screw 23. The yarn is guided outof the device by a porcelain V-guide 24 mounted in a bracket 25, thelower part of which is slotted similarly to the lug 21 and is secured tothe flange 9 by means of a screw 26. Beneath the plate 6 is fitted aU-shaped clip 27 secured by means of screws 28 and enabling the tensiondevice to be mounted on a horizontal rail 29 of a textile machine inwhich the tension device is to be used, for example a pirn windingmachine.

In the operation of the device when the yarn 18 is running through thedevice, tension in the yarn, acting on the crown of the ridge 17 of theupper friction element 15, lifts that element out of contact with thelower friction element 14. The pressure of the yarn against thefrictionv elements is thus solely due to the tension in the yarn as itpasses in contact with them, and the tension in the yarn is accordinglyincreased by its passage through the device to a degree depending on thetotal angle through which the yarn is deected by its contact with thefriction surfaces. Thus, the higher the tension in the yarn the less`will be the ratio in which the tension is multiplied by its passagethrough the device.- When, for any reason, the yarn ceases to be drawnthrough the device, which would be liable to allow the tension in theyarn to fall to zero, the upper friction element drops into engagementwith t-he lower friction element 14, nipping the yarn 18 at two pointsbetween the ridge 17 andthe groove 16 so that tension can be maintainedon the output side of the tension device. In this way the device is ableto maintain a substantial degree of tension on the stationary yarnwhich, however, does not unduly increase when the yarn is caused' to runthroughthe device or when the speed of the running yarn increases.

The increase of tension imparted by the device can be adjusted byvarying the position of the spindle 11 along the slot 10,1 and also byvarying the total weight of the upper` friction element 15. This can bedone by adding ori 'removing tension weights in the form of washersindicated at 30 in Figure l. If desired, the elements 14, 15 can bereversed, the member 14 being used as the upper and 1 5 as. the lowerfriction element. This enables a larger number of tension weights 30 tobe used, accommodated in thewell ofthe inverted element 14. The element154 rests with its projecting flange 31 in contact with the base plate6. The adjustability of the guides 19 and 24 enables their height to bereduced so asto lead the yarn accurately through the device when theelements are inverted. The yarn entering the device may be arranged,also by the adjustment ofthe height of the guide eyeV 19, at a slightangle to the horizontal as shown in Figure 1.

'Ihisenables the frictional engagement with the yarn ofthe upper orllower friction member to be varied so as to ensure a slow rotation ofthe elements during the operation of the device, by which wear on theelements is distributed round their whole periphery.

t The device shown inl Figures 3 and 4 comprises a sheet metal baseplate 36 on which rests a cylindricalbase block 37' secured thereto bymeans of a central spindle 38 whose lower end is screw-threaded into thebase block 37 and the base. plate 36, the assembly being tightened bymeans of a 1o ck nutv 391 lying over the base block. The upper end ofthe central spindle 38 terminates in a sharp conical poi-nt'. Over thespindle is slipped a sleeve 40 whose upper` endl is closed by a screw 41having a conical recess at itstip into which the point of the centralspindle 38i enters so as tol carry the weight of the sleeve 40. To thelower end of the sleeve 40 is fixed a fibre pulley 4Z with a V'v-grooveround its edge, which is suspended'j-ustA clear of the lock nut 39.

Over base block 37 is placed the lower friction element;` 14, similarto. that of' Figure l, the skirt of the member: restingV on the baseplate 36, and being centredby meansA of three short pins 43- extendingupwards through the. base plate andi disposed symmetrically roundlthespindle 38. The central hole in the member 14 accommodates thelock-nut 39 and part of the pulley 42, the

bottom of'-r the pulley groove being just level with the upper` surfaceofthe element 14.

The upper friction element- 45 is similar to the element; 115. ofFiguresl 1 and 2, but is carried by: a cap 46 whose depending edges aresecured to the upstanding liange 31, the middle of the cap being in theform of an upwardly extending tube 47 surrounding and closely fittingthe sleeve 40. The sleeve 40 is formed externally with a helical groove48. of about 1 pitch and $46. Width, into which firs thc inner, ccd cia. Pin, 49 driven.

The yarn is guided horizontally into the device by means of a porcelaineye 19 and balloon plate 20 similar to those of Figures l and 2 butmounted in a vertical plane. A lug 51 extending downwards from the loweredge of the plate 20 is bent laterally and upwards, and is bolted to adownwardly extending ange 52 formed by bending down one edge of the baseplate 36. The downwardly extending flange 52 also has bolted to it a U-shaped clip 53 for securing4 the tension device to a vertical pillar 54of the machine in which the tension device is to be used, e. g. awarping creel. The balloon, plate 20 can be twisted about a verticalaxis to face the direction from which the yarn is to reach the tensiondevice'. The yarn, after passing through the porcelain eye 19 entershorizontally between the lower and upper friction elements 14, 45,crosses the line of the ridge 17 and groove 16 in those elements, passesi-nto driving contact with the bottom of the V-groove in the bre pulley42, and again crosses the line of the ridge 17 and groove 16. to`proceed to the point where the yarn is to be used. As in Figures l andl2,: the higher the tension in the yarn, the less will be the degree towhich the tension is increased by its passage through tlie device. Inaddition, however, the yarn engaging the fibre pulley 42k tends torotate the sleeve 40 on which the fibre pulley is mounted at a greaterangular speed than the upper friction member 45. This tendency, actingthrough theA helical groove 48 formed in the sleeve, and through the pin49 engaging that groove, tends to lift the upper friction element 45still further out of engagement with the lower friction element 14 andstili' further reduces the degree by which the yarn tension is increasedby its passage through the device.

While in Figures 1 and 3, the element 14 is shown with a single groovel16, and the elements 14, 45 with a single matching ridge 17,'aplurality of grooves 16 may b e pro,- vided if desired, as shown inFigure 5.

Having described my invention, what I desire to secure by Letters Patentis;

yl'. A yarn tension device comprising a central spindle,y a pair offriction elements disposed face-to-face and mounted for the rotation ofat least one of said elements about said spindle by the passage of ayarn between said elements, means for pressing said elements togetherupon said yarn and means actuated by the rotation of one of saidelements toA urge said elements apart against the action of saidpressing means, so as to reduce the pressure on said yarn.

2*."AY yarn tension device comprising a central spindle, av pair offriction elements disposed face-to-face and mounted for the rotation ofat least one of` said elements about said spindle by the passage of ayarn between said elements,l means for pressing said elements togetheruponV said yarn, and' a rotatable sleeve interposed between saidspufindle` and' said rotatable element, said sleeve and said' rcfctabllcclcmclif being furnished, cncv with a, hclical groove and. theother witha projection` engaging said groove, s aid sleeve and said rotatableelement 4being adapted to rotate to different extents so that saidrotatable element isl urged` by thev engagement between said helicalgroove and said projection against the action of said pressing means, soas to reduce the pressure uponsaid yarn.v

3. A yarn tensionV device comprising a centralv spindle, a pair offriction elements disposed face-to-face and mounted for the rotation ofat least one of said elements about saidspindle by the passage of a yarnbetween said elements, means for pressing said elements together uponsaid" yarn, a rotatablesleeve interposed between said spindle and s aidlrotatable element, and a pulley mounted, on said sleeve and adapted tobe engaged by s aid yarn in passing between said friction elements, saidsleeve and said rotatable element being furnished one with a helicalgroove andthe other with a projection engaging said groove, said sleeveand said rotatable element beingk adapted to, rotate to differentextents so thatsaid rotatable element isC urged by. thc, cnscgcmcntbctwccn. Said. hclical grccvc and: Said projection against the action ofsaid pressing means, so means actuated by the rotation of one of saidelements to as to reduce the pressure upon said yarn. urge said elementsapart against the action of said press- 4. A yarn tension devicecomprising a central spindle, ing means, so as to reduce the pressure onsaid yarn.

a pair of friction elements disposed face-to-face and mounted for therotation of at least one of said elements 5 References Cited m the le ofthls patent about said spindle by the passage of yarn between them,UNITED STATES PATENTS one of said elements being provided with at leastone 849,295 Wardwell Apr. 2, 1907 projecting annular ridge and the otherwith at least one 1,630,426 Hasbrouck May 3l, 1927 groove matching andregistering therewith, pressing means 2,124,422 Klein July 19, 1938 forpressing said elements together upon said yarn and 10 2,624,527 VonKohorn Jan. 6, 1953

